Prep the chicken: Pat the sliced chicken dry with paper towels. Toss with 2 tablespoons cornstarch and a pinch of salt and pepper. This helps the chicken brown and stay tender.
Mix the sauce: In a bowl or measuring cup, whisk soy sauce, oyster sauce, rice vinegar, honey, sesame oil, sriracha, broth, and 2 teaspoons cornstarch.
Set aside.
Heat the pan: Place a large skillet or wok over medium-high heat. Add 1 tablespoon oil and swirl to coat.
Sear the chicken: Add chicken in a single layer. Cook 3–4 minutes per side until lightly browned and cooked through.
Work in batches to avoid steaming. Transfer to a plate.
Stir-fry the veggies: Add a small splash of oil if the pan is dry. Cook onion, bell peppers, carrot, and broccoli for 3–4 minutes, stirring often.
Add snap peas, garlic, and ginger. Cook 1–2 more minutes until crisp-tender.
Combine and sauce: Return chicken to the pan. Whisk the sauce again, then pour it in.
Stir constantly for 1–2 minutes until the sauce thickens and coats everything.
Taste and adjust: Add more soy for salt, vinegar for brightness, or honey for sweetness. Sprinkle sesame seeds if using.
Portion for meal prep: Divide rice or cauliflower rice into 4–5 containers. Top with stir fry.
Let cool uncovered for 10–15 minutes before sealing.